Optical and Spectroscopic Properties of Lorenzenite, Loparite, Perovskite, Titanite, Apatite, Carbonates from the Khibiny, Lovozero, Kovdor, and Afrikanda Alkaline Intrusion of Kola Peninsula (NE Fennoscandia)

Miłosz Huber,Daniel Kamiński,Evgeni Kozlov,Grzegorz Czernel

doi:10.3390/cryst12020224

Abstract

This manuscript deals with the analysis of significant rare earth elements (REE) minerals such as eudialyte, lorenzenite, loparite, perovskite, titanite, apatite, and carbonates. These minerals are found in the rocks of the Khibiny, Lovozero, Afrikanda, and Kovdor massifs (the Paleozoic hotspot activity in the Kola-Karelian Alkaline Province is estimated at about 100,000 km2). Performed microscopic analyses that demonstrated their structure and optical features (dimming, interference colors, relief). Single-crystal analysis using XRD methods, SEM-EDS, and spectroscopic (FTIR) studies allowed the characteristics of described minerals: Lorenzenite in Lovozero probably crystalized after loparite have small additions of Nb, La, Ce, Pr, and Nd. Loparite and perovskite have the addition of Ce, Nb, and Ta. The same dopants have titanite probably crystalized after perovskite. Calcite in these massifs had the addition of Ce and Sr, the same as in fluorapatite, which was found in these rocks too. All of the analyzed minerals are REE-bearing and can be considered as deposits.

Highlights

The Kola-Karelian Alkaline Province is a unique world complex containing about forty different intrusions of ultramafic alkaline rocks with rare rock and mineral types [1,2,3,4]
To better describe the mineralogy of the phases discussed in the title, the main features of the most important rocks of the massifs are briefly presented: Khibiny, Lovozero, Afrikanda, and Kovdor
Ore minerals are represented by ilmenite and titanite less frequently, loparite, pyrite, magnetite

Summary

Introduction

The Kola-Karelian Alkaline Province is a unique world complex containing about forty different intrusions of ultramafic alkaline rocks with rare rock and mineral types [1,2,3,4]. The minerals lorenzenite, loparite, perovskite, titanite, apatite, and carbonate, among others, are found in these rocks and are admixtures in the discussed rocks. On the other hand, is found in the urtite formations of the Lovozero and Kovdor rocks Besides these minerals, apatite is found in whole rocks of described massifs and is accompanied by minerals such as titanite containing REE admixtures. Apatite is found in whole rocks of described massifs and is accompanied by minerals such as titanite containing REE admixtures In addition to these minerals, perovskite and carbonate (contain admixtures of Sr and Ce) are found in Afrikanda in ultramafic-alkaline rocks [6,7,8,9,10,11,12].

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Discussion

Conclusion